Hello everyone,
I'm posting here to get some feedback about my new alarm circuit:
I need only to output a fairly strong frequency, used as an audio indicator, nothing related to music.
The frequency is from few Hz to 5KHz, and needs to be heard let say when driving a bike.
The volume has to be ajustable (from CPU)
Average current drawn from battery must be less than 1mA as the application run with a coin cell battery.
Since piezo ceramic buzzer need from 10 to 30V, extra circuitery are requiered.

A capacitor booster with diode, using a PWM at 100KHz and changing the duty to change the volume.
The consumption is less 1mA at full volume, and nothing when, no output as I can switch down the PWM (signal and booster)

The problem is the board space used with this solution.

So I wonder if any one can submit me a new design (like using push pull or so) to reduce the number of capacitor/diode while still being cheap.